Details in retopology
You could continue to retopologize over this incision. 
When your retopology is over, you would UV unwrap it, and do some displacement map baking, or normal map baking. 

Then you can use the baked displacement (or normal map) textures on your retopologized model. So the incision would not be in the topology, but in the texture (normal map, or displacement). So it would be visible in your render.